Bulletin of the American Physical Society
APS March Meeting 2020
Volume 65, Number 1
Monday–Friday, March 2–6, 2020; Denver, Colorado
Session B24: Systems Far from Equilibrium |
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Sponsoring Units: GSNP Chair: John Bechhoefer, Simon Fraser University Room: 401 |
Monday, March 2, 2020 11:15AM - 11:27AM |
B24.00001: Thermodynamic uncertainty relations and fluctuation theorems for Bayes nets David Wolpert The pioneering paper [1] analyzed the non-equilibrium statistical physics of a set S of multiple interacting systems whose joint discrete-time evolution is specified by a Bayesian network. Their major result was an integral fluctuation theorem (IFT) governing the sum of two quantities: the entropy production (EP) of an arbitrary single one of the systems, v ∈ S, and the transfer entropy from v to the other systems in S. |
Monday, March 2, 2020 11:27AM - 11:39AM |
B24.00002: Nonequilibrium fluxes in steady state: connection with boundary conditions Caleb Wagner, Michael Hagan, Aparna Baskaran A characteristic feature of nonequilibrium steady states is their ability to maintain nonzero fluxes in steady state. Here I will discuss mass fluxes in a class of nonequilibrium systems characterized by driving at the level of individual particles. By constructing an explicit mathematical representation of the full nonequilibrium steady state, I am able to quantitatively connect mass fluxes in the bulk with the boundary conditions. In particular, the emergence of nonzero mass fluxes is tied to the breaking of detailed balance at the boundaries. |
Monday, March 2, 2020 11:39AM - 11:51AM |
B24.00003: Unifying Thermodynamic Uncertainty Relations Gianmaria Falasco, Massimiliano Esposito, Jean-Charles Delvenne We introduce a new technique to bound the fluctuations exhibited by a physical system, based on the Euclidean geometry of the space of observables. Through a simple unifying argument, we derive a sweeping generalization of so-called Thermodynamic Uncertainty Relations (TURs). We not only strengthen the bounds but extend their realm of applicability and in many cases prove their optimality, without resorting to large deviation theory or information-theoretic techniques. In particular, we find the best TUR based on entropy production alone and also derive a novel bound for stationary Markov processes, which surpasses previous known bounds. Our results derive from the non-invariance of the system under a symmetry which can be other than time reversal and thus open a wide new spectrum of applications. |
Monday, March 2, 2020 11:51AM - 12:03PM |
B24.00004: Non-Gaussian diffusion and energy balance of a Brownian particle in active baths Jin Tae Park, Govind Paneru, Chulan Kwon, Steve Granick, Hyuk Kyu Pak We present a minimal model to generalize the iconic feature of active matter that Brownian particles diffusing in a harmonic potential are kicked by external forces to engender mobility beyond that attributable to thermal energy. The wide time and length scales of usual active matter systems are mapped onto the generic concept of a single Brownian diffusion time (a particle diffusing in a harmonic potential) and kicks from external forces that arrive at random intervals with a defined, programmable, duration time for each kick. Our experiments using an optical trap agree in showing enhanced diffusion that is Gaussian only if the kick duration time is larger than the Poisson interval time. In addition, we conclude that maximum energy dissipation occurs at the time-scale of the geometric mean of the kick duration time and the particle thermal equilibration time. Usual active matter systems do not allow this independent variation of thermal motion, active motion, and the relative time scales of both. In this streamlined system they are varied independently, allowing one to rapidly prototype the limits of various stochastic thermodynamic models. |
Monday, March 2, 2020 12:03PM - 12:15PM |
B24.00005: Periodic driving in a two-dimensional Brownian ratchet Todd Gingrich, Nils Strand, Rueih-Sheng Fu Brownian dynamics on a fixed potential landscape generates no steady-state current, but currents can be obtained by periodically switching between multiple landscapes. Even more interesting than the existence of such ratcheted currents is that the direction of the current can depend on the frequency of the switching. I will present numerical work on the behavior of current reversals in a two-dimensional system. I will discuss our efforts to make sense of the system by conditioning a time-periodic Markov process for a coarse-grained model. Interestingly, the low-frequency asymmetry between leftward and rightward motion appears at the level of typical events, but the high-frequency asymmetry only emerges for atypical events. |
Monday, March 2, 2020 12:15PM - 12:27PM |
B24.00006: Equation of State for a Far-from-equilibrium Thermodynamic System with Emergent Scales at Steady-state ATANU CHATTERJEE, Germano S Iannacchione One of the hallmarks of soft-condensed matter systems is their ability to exhibit emergent order - spanning a wide range of length and time-scales - when driven out-of-equilibrium. Some of these patterns emerge and disappear at sub-nanosecond scales while some are large enough that they can be physically measured. We present a field theoretic formalism by defining the Lagrangian density as a function of a generic thermodynamic scalar. Our definition of the thermodynamic Lagrangian density involves two components, the internal work or the coherent part which gives rise to emergent order, and the internal dissipation or the incoherent part which acts as the internal sink. The salient feature of this formulation is that it takes into account the spatial and temporal gradients of the generic thermodynamic scalar as the system is driven out-of-equilibrium. On minimizing the action and solving the Euler-Lagrange equations, we obtain a generalized thermodynamic equation of state. |
Monday, March 2, 2020 12:27PM - 12:39PM |
B24.00007: Thermodynamic Analysis of Non-Ergodic and Asymmetric Dimension Yu Qiao We report an interesting Monte Carlo simulation result of a Billiard-type model system, wherein two larger ergodic areas are separated by a small non-ergodic barrier. The two ergodic areas have different heights in a gravitational field. In-plane pressure does work to the lower “plain” when the plain area varies, and gravitational force does work to the upper “plateau” when the plateau height changes. The steady-state is defined by the macroscopic variables measured from the system surface. The simulation results indicate that the particle density ratio spontaneously follows a non-Boltzmann distribution and remarkably, in an isothermal cycle the produced work is significantly greater than the consumed work. The non-ergodic barrier, referred to as the non-ergodic and asymmetric dimension (NEAD), is not “Maxwell’s demon”. Its operation does not require detailed knowledge of system microstate. The particle motion is unmonitored, unforced, and random. The explanation of the system performance should be unrelated to the physical nature of information. The concept of NEAD is also being investigated experimentally, through the measurement of the cross-influence of chemical potential and electric potential of large ions confined in small nanopores. |
Monday, March 2, 2020 12:39PM - 12:51PM |
B24.00008: Bounds on current fluctuations for periodically driven systems Karel Proesmans The thermodynamic uncertainty relation, in its original form, bounds the amount current fluctuations can be suppressed in terms of the dissipation in a mesoscopic steady-state system. We extend such bounds to systems with time-periodic driving, where they lead to a bound for the hysteresis of any thermodynamic flux. Our results are illustrated on the work fluctuations of an expanding gas. |
Monday, March 2, 2020 12:51PM - 1:03PM |
B24.00009: Entropy production bounds under Hamiltonian and rate matrix constraints Artemy Kolchinsky, David Wolpert Entropy production (EP) is a fundamental measure of the thermodynamic inefficiency of a physical process. If there are no constraints on the rate matrices and Hamiltonians available to a driving protocol, one can transform a system from any initial Hamiltonian and state distribution to any final Hamiltonian and state distribution with zero EP. We investigate the minimal EP that must be incurred to implement such a transformation, if there are constraints on the set of allowed Hamiltonians and rate matrices. Our first result is that zero EP can be achieved even when the Hamiltonian has only a single controllable degree of freedom, as long as there are no constraints on the rate matrix (beyond detailed balance). We then derive non-trivial bounds on the EP that arise from the presence of simultaneous constraints on the Hamiltonian and the rate matrix. These bounds are determined by an effective non-equilibrium free energy, which reflects the work value of a distribution and Hamiltonian under a set of constraints. |
Monday, March 2, 2020 1:03PM - 1:15PM |
B24.00010: Pre-Cooling Strategy Can Generate Exponentially Faster Heating Oren Raz, Amit Gal What is the fastest way to heat a system which is coupled to a temperature controlled oven? The intuitive answer is to use only the hottest temperature available. However, we show that in some cases it is possible to achieve an exponentially faster heating, and propose a strategy to find the optimal protocol. Surprisingly, this protocol can have a pre-cooling stage: cooling the system before heating it shortens the heating time significantly. This approach can be applied to many-body systems, as we demonstrate in the 2D antiferromagnet Ising model. |
Monday, March 2, 2020 1:15PM - 1:27PM |
B24.00011: The solution of the Metropolis dynamics on a complete graph with applications to anomalous thermal relaxations Marija Vucelja, Israel Klich We find analytically the complete set of eigenvalues and eigenvectors associated with Metropolis dynamics on a complete graph. As an application, we use this information to study an unusual relaxation phenomenon, called the Mpemba effect. This effect describes situations when, upon performing a thermal quench, a system prepared in equilibrium at high temperatures relaxes faster to the bath temperature than a system prepared at a temperature closer to that of the bath. |
Monday, March 2, 2020 1:27PM - 1:39PM |
B24.00012: Out-of-equilibrium chemical networks: dissipation shapes selection Daniel Maria Busiello, Shiling Liang, Paolo De Los Rios Life has most likely originated as a consequence of processes taking place in non-equilibrium conditions (e.g. in the proximity of deep-sea vents) selecting states that would have been otherwise unfavorable at equilibrium. Here we present a simple chemical network in which the selection of states is driven by the dissipation rate, as previously suggested in the literature: states participating to faster reactions dissipate faster and are the most populated ones in non-equilibrium steady-state conditions. Building upon these results, we show that, as the complexity of the chemical network increases, the velocity of the reaction path leading to a given state determines its selection, giving rise to phenomena of global localization in state space. A byproduct of our studies is that, in the presence of a temperature gradient, thermophoresis-like behavior inevitably appears depending on the transport properties of each individual state, thus hinting at a possible microscopic explanation of this intriguing and long-standing phenomenon. |
Monday, March 2, 2020 1:39PM - 1:51PM |
B24.00013: Isometric uncertainty relations Hadrien Vroylandt, Karel Proesmans, Todd R Gingrich We generalize the link between fluctuation theorems and thermodynamic uncertainty relations by deriving a bound on the variance of fluxes that satisfy an isometric fluctuation theorem. The resulting bound, which depends on the system's dimension d, naturally interpolates between two known bounds. The bound derived from the entropy production fluctuation theorem is recovered for d=1, and the original thermodynamic uncertainty relation is obtained in the d→∞ limit. We show that our result can be generalized to order parameters in equilibrium systems, and we illustrate the results on a Heisenberg spin chain. |
Monday, March 2, 2020 1:51PM - 2:03PM |
B24.00014: Quantum Thermodynamics of a Spin one System Mulugeta Bekele We take a collection of large non-interacting spin one particles, each having an electric dipole of |
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B24.00015: Stochastic Thermodynamics with both Even and Odd Controlling Parameters Zhanchun Tu Shortcuts to isothermality inspired development of stochastic thermodynamics with both even and odd controlling parameters. was developed to understand nonequilibrium phenomena of small systems. It is found that the definition of heat and the microscopically reversible condition are incompatible for small systems with odd controlling parameters. Such a contradiction also leads to a revision to the fluctuation theorems and nonequilibrium work relations. By introducing adjoint dynamics, we find that the total entropy production can be separated into three parts, with two of them satisfying the integral fluctuation theorem. Revising the definition of heat and the microscopically reversible condition allows us to derive two sets of modified nonequilibrium work relations, including the Jarzynski equality, the detailed Crooks work relation, and the integral Crooks work relation. |
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